16499681 has 6 divisors (see below), whose sum is σ = 18136146. Its totient is φ = 14999600.

The previous prime is 16499647. The next prime is 16499689. The reversal of 16499681 is 18699461.

It can be written as a sum of positive squares in only one way, i.e., 16120225 + 379456 = 4015^2 + 616^2 .

It is not a de Polignac number, because 16499681 - 2⁶ = 16499617 is a prime.

It is a super-2 number, since 2×16499681² = 544478946203522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16499689) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 68060 + ... + 68301.

It is an arithmetic number, because the mean of its divisors is an integer number (3022691).

Almost surely, 2^16499681 is an apocalyptic number.

16499681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16499681 is a deficient number, since it is larger than the sum of its proper divisors (1636465).

16499681 is a wasteful number, since it uses less digits than its factorization.

16499681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136383 (or 136372 counting only the distinct ones).

The product of its digits is 93312, while the sum is 44.

The square root of 16499681 is about 4061.9799359426. The cubic root of 16499681 is about 254.5805278318.

The spelling of 16499681 in words is "sixteen million, four hundred ninety-nine thousand, six hundred eighty-one".